Diminished Reactivity of Ortho-Substituted Phenacyl Bromides toward Nucleophilic Displacement

2003 ◽  
Vol 68 (4) ◽  
pp. 1594-1596 ◽  
Author(s):  
Diane M. Kalendra ◽  
Barry R. Sickles
Keyword(s):  
Nucleophilic Displacement ◽  
Phenacyl Bromides

Bifluoride Ion Mediated SuFEx Trifluoromethylation of Sulfonyl Fluorides and Iminosulfur Oxydifluorides

2018 ◽  
Author(s):  
Christopher J. Smedley ◽  
Bing Gao ◽  
Suhua Li ◽  
Qinheng Zheng ◽  
Andrew Molino ◽  
...  
Keyword(s):  
Breast Cancer Cells ◽  
Catalytic Mechanism ◽  
Bioactive Molecules ◽  
Chromatographic Purification ◽  
Rapid Exchange ◽  
Nucleophilic Displacement ◽  
Sulfur Fluoride ◽  
Reactions With Nucleophiles ◽  
New Generation ◽  
Selection Of

Sulfur-Fluoride Exchange (SuFEx) is the new generation click chemistry transformation exploiting the unique properties of S-F bonds and their ability to undergo near-perfect reactions with nucleophiles. We report here the first SuFEx based protocol for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from the corresponding sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new protocol involves the rapid exchange of the S-F bond with trifluoromethyltrimethylsilane (TMSCF<sub>3</sub>) upon activation with potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative catalytic mechanism is proposed supported by DFT calculations, involving formation of the free trifluoromethyl anion followed by nucleophilic displacement of the S-F through a five-coordinate intermediate. The preparation of a benzothiazole derived bis(trifluoromethyl)sulfur oxyimine with cytotoxic selectivity for MCF7 breast cancer cells demonstrates the utility of this methodology for the late-stage functionalization of bioactive molecules.<br>

Reactions of Bis(phenyldiazenido)rhenium Complex [ReBr2(NNPh)2(PPh3)2]Br with Carbon Monoxide and Alk-1-ynes

2007 ◽  
Vol 72 (5-6) ◽  
pp. 599-608 ◽  
Author(s):  
Maria Teresa A. R. S. da Costa ◽  
Maria Fátima C. Guedes da Silva ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Carbon Monoxide ◽  
Rhenium Complex ◽  
Nucleophilic Displacement

The conversion of the bis(diazenido) complex [ReBr2(NNPh)2(PPh3)2]Br (1) to the mono(diazenido) complex [ReBr3(NNPh)(PPh3)2] (2) is promoted by alk-1-ynes, whereas the reaction with CO leads to the mixed dicarbonylmono(diazenido) Re(III) species [ReBr(CO)2- (NNPh)(PPh3)2]Br (3). Both reactions are suggested to occur via related pathways involving a nucleophilic displacement of one of the diazenide ligands by Br-. Reduction of the phenyldiazenide ligand in 2 occurs in the attempted reaction with HC≡CPh to give the nitrido complex [ReBr2(N)(PPh3)2] (4) and the bis(diazenido) species [ReBr2(NNPh)2(PPh3)2] (5) and [ReBr(NNPh)2(PPh3)2] (6).

scholarly journals An efficient and practical chemo-enzymatic route to (3R,3aR,6R,6aR)-hexahydrofuro[3,2-b]furan-6-amino-3-ol (6-aminoisomannide) from renewable sources

SynOpen ◽  
2021 ◽  
Author(s):  
Valerio Zullo ◽  
Antonella Petri ◽  
Anna Iuliano
Keyword(s):  
Hydroxy Group ◽  
Sodium Azide ◽  
Hydroxyl Group ◽  
Azido Group ◽  
One Pot ◽  
Renewable Sources ◽  
Nucleophilic Displacement ◽  
Trifluoromethanesulfonic Anhydride ◽  
Enzymatic Route

The synthesis of 6-aminoisomannide is easily achieved starting from the renewable, inexpensive and commercially available isosorbide, in 66% overall yield. A biocatalysed highly regioselective acetylation of the 3-endo hydroxyl group of isosorbide was followed by the stereospecific interconversion of the 6-exo hydroxyl group into azido group, through reaction with trifluoromethanesulfonic anhydride followed by nucleophilic displacement of the triflate group by sodium azide. Finally, reduction of the azido group and deacetylation of the 3-hydroxy group were performed one pot by using LiAlH4.

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